1. Field of the Invention
The present invention relates to a weld configuration for adjacent cylindrical pipe members such as rotor discs in a gas turbine engine, and a method of heating one of the tubes or discs prior to joining to provide a tight fit to hold the discs together for welding.
2. Description of the Related Art Including Information Disclosed Under 37 CFR 1.97 and 1.98
In a gas turbine engine, a series of rotor discs are joined together to form a rotor assembly. Adjacent discs are generally bolted or welded together, or both. Prior art welds between adjacent rotor discs allow for high stresses to act along the weld joints. One early method for welding rotor discs is shown in the U.S. Pat. No. 3,067,490 issued to Luthy et al on Dec. 11, 1962. This invention shows two rotor discs welded together along an overlapping cylindrical lip. This joint configuration still allows for high stress loads along the weld joint.
U.S. Pat. No. 2,555,924 issued to Faber on Jun. 5, 1951 shows a Fluid Cooled Rotor Structure in which rotor discs are welded together along an interface, the interface having coordinating step portion formed within the discs. This weld, like the previous Luthy weld, still does not provide the reduction in stress loads at the weld as does the present invention.
U.S. Pat. No. 2,200,287 issued to Lysholm on May 14, 1940 shows a Turbine with rotor discs welded along step portions of the disc similar to the Luthy and Faber patents described above. The Lysholm rotor disc weld also lacks the stress reduction of the present invention.
It is an object of the present invention to provide for an improved weld joint in a weld between joined members in which the weld interface carries a structural load of the two members.
It is another object of the present invention to provide for an improved weld between two pipe members.
It is another object of the present invention to improve the service like of a rotor disc assembly in a gas turbine engine.
It is also an object of the present invention to provide a weld structure for tube or pipe assembly like that in rotor discs in a gas turbine engine that provides for reduced stress concentrations that would result across the welds. These objects of the invention and how they are accomplished are described below in the detailed description of the present invention.